Bazel extensions for pybind11

Provided rules:

pybind_extension: Builds a python extension, automatically adding the required build flags and pybind11 dependencies. It defines a *.so target which can be included as a data dependency of a py_* target.
pybind_library: Builds a C++ library, automatically adding the required build flags and pybind11 dependencies. This library can then be used as a dependency of a pybind_extension. The arguments match a cc_library.
pybind_library_test: Builds a C++ test for a pybind_library. The arguments match a cc_test.

To test a pybind_extension, the most common approach is to write the test in python and use the standard py_test build rule.

Installation

In your WORKSPACE file:

http_archive(
  name = "pybind11_bazel",
  strip_prefix = "pybind11_bazel-<stable-commit>",
  urls = ["https://github.com/pybind/pybind11_bazel/archive/<stable-commit>.zip"],
)
# We still require the pybind library.
http_archive(
  name = "pybind11",
  build_file = "@pybind11_bazel//:pybind11.BUILD",
  strip_prefix = "pybind11-<stable-version>",
  urls = ["https://github.com/pybind/pybind11/archive/v<stable-version>.tar.gz"],
)
load("@pybind11_bazel//:python_configure.bzl", "python_configure")
python_configure(name = "local_config_python")

Then, in your BUILD file:

load("@pybind11_bazel//:build_defs.bzl", "pybind_extension")